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WALTER S. HUNTER 



whistle A. Later during the control tests -another Galton 

 whistle was used, whistle B. B was a new instrument and was 

 accepted as standard. Its tonal divisions were lower in pitch 

 than those of A, so that 3413.3 on A was equaled by 3906.17 

 on B, using the same air pressure. (These measurements are 

 very close approximations.) Pitches are always stated in 

 terms of B. 



In these tests the problem set the rat was the associating 

 of a turn to the right for food with the whistle tone and a turn 

 to the left for food with the absence of the whistle. 10 trials 

 daily were given with punishment and reward. The period of 

 learning plus the control period extended from April 17, 1914 

 to October 17, 1914. 



Table 4 gives the results on learning. Rat 44 was dropped 

 at the end of 650 trials because of an incurable habit of always 

 going to the right whether the stimulus was sounded or not. 



The problem was considered learned by rat 46 at the end of 

 730 trials, and by rats 45 and 47 at the end of 960 trials. Con- 

 trols were then instituted. 



